The present invention relates to a process and apparatus for the reduction of alcohol in fermented beverages. More particularly, the present invention relates to a process and apparatus for reducing the alcohol (i.e. ethanol) content of wine.
The challenge when reducing the alcohol content of wine is to:    1. not cause heat damage to the wine;    2. cause minimal water loss from the wine during the alcohol reduction process; and    3. retain in, or return to the wine as much aromatics and flavour components as possible.
In most wine producing countries, it is illegal to dilute wine with water. It is generally not illegal to adjust the taste of wine by removing constituents like acids. Except for a few countries, it is generally not illegal to remove alcohol from wine. It has become standard practice in hot climates, where grapes develop high sugar levels (and therefore, high alcohol content), to practise alcohol reduction techniques on the wine produced.
A variety of processes for removing select component parts from beverages are known. For example, evaporation technology is generally used to remove water from fruit juice and thereby concentrate the fruit juice. However, no feedback loop to re-introduce water evaporated from the feedstock fruit juice back into the evaporation chamber exists, causing the feedstock fruit juice to concentrate, and the operating temperature in the evaporation chamber consequently to rise. Drawbacks of evaporation chambers are that they result in significant water loss from the feedstock juice and their operating temperatures would cause heat damage to a wine feedstock.
Other technologies directed specifically at the removal of alcohol are also known. An example is the membrane processes, which extracts an alcohol-rich permeate stream from wine under pressure. Drawbacks of this process are that: the equipment is expensive; the membranes have a limited lifespan; and the high pressure required makes this process energy intensive. A further example is the spinning cone column used by ConeTech, in which the wine is subjected to low-pressure heating in a column equipped with fast-rotating cones to drive off a portion of the alcohol. A drawback of this process is that, in addition to removing alcohol, many of the flavour components are also removed from the wine and need to be recovered and added back to the wine if the original flavour profile of the wine is to be retained. Another drawback is the inability of the ConeTech technology to concentrate the alcohol stream removed from the wine, resulting in undesirable loss of water from the de-alcoholised wine. A further drawback of the ConeTech technology is that its column includes many internal moving parts rotating at high speed, making the equipment expensive and energy and maintenance intensive.
The process and apparatus according to the present invention aims to address the above drawbacks and challenges.